Renal System Flashcards
How much blood is filtered through the kidneys everyday?
120-140 L of blood
What is the filtering unit of the kidneys?
Nephrons
What are the 2 substances the glomerulus cannot filter?
- Blood cells
- Proteins
What are the 2 sides of the tubules and what side are they on?
Basal lateral - side with bloodstream
Apical - side w/o bloodstream
Why are the gaps in the filtration membrane negatively charged?
To keep the proteins and RBCs out
What drives filtrate across the walls of the glomerulus?
Pressure gradient
If you have LOW blood pressure, how would the arteries compensate?
Afferent: dilate
Efferent: Constrict
Renin is released by what?
Juxtaglomerular cells
What does renin do and how does it know when to act
- begins the transformation of angiotensinogen to angiotensin 1
- responds to LOW BP
Where is ANP released?
The heart
What does ANP respond to?
Increased blood volume
What does ANP actually do? (2)
- decreases sodium reabsorption (more sodium will exit) therefore as water follows solute, more water will exit the body and the blood volume will decrease
- dilates blood vessels to lower BP
What do juxtaglomerular cells do and why?
secrete renin when BP is low
What does renin trigger?
The transformation of angiotensinogen to angiotensin 1
What turns angiotensin 1 into angiotensin 2?
ACE enzyme
What does angiotensin 2 do? (2)
Increases BP by vasoconstriction and INCREASES sodium reabsorption
- therefore decreasing urine volume
What do macula densa cells respond to?
changes in solute of the DCT
What will macula densa cells secrete if there is too much solute in the DCT?
Adenosine
What does adenosine do to the afferent arterioles?
constricts afferent arterioles to decrease GFR
Where is ACE mainly produced, although in most parts of the body?
Lungs
